<AWT Dev> KDE Task bar is always on top of fullscreen Java applications

[Anthony Petrov]

Phil: Ah, right! Haven't used to the new rules yet. Thanks for reminding 
us about that.

Julien: I have a few questions about your patch:

1. The xprop output that you've attached to the KDE bug report [1] 
indicates that the full screen window is maximized (i.e. using the 
emulated full screen mode rather than the exclusive one). In this case, 
the behavior is correct. But I assume you did try to do the same with 
the exclusive FS mode enabled, didn't you? Could you please provide an 
xprop output in that case, too?

2. The EWMH specification [2] states that "A Client wishing to change 
the state of a window MUST send a _NET_WM_STATE client message to the 
root window". However, your proposed patch calls XChangeProperty() which 
changes the property manually, and therefore violates the EWMH spec. I 
think that a subsequent XSendEvent() to the root window should be enough 
for our purposes.

3. The comments at the KDE bug report, as well as the EWMH spec (see the 
"Stacking order" section) suggest that a window with the 
_NET_WM_STATE_FULLSCREEN state should already be above any other windows 
(including the _NET_WM_STATE_ABOVE windows). Also, the specification 
states that the latter state should not be used by applications 
directly. Note that the function X11GD_SetFullscreenMode() which you're 
changing with your patch already sets the _NET_WM_STATE_FULLSCREEN state 
to the full screen window, and, according to the EWMH specification, 
that alone should work fine for full screen windows. So doesn't this 
then seem to be a bug in KDE4 actually?

[1] https://bugs.kde.org/show_bug.cgi?id=276159

[2] http://standards.freedesktop.org/wm-spec/wm-spec-latest.html

--
best regards,
Anthony

On 6/28/2011 8:26 PM, Phil Race wrote:
> Anthony,
> 
> That looks like a "small patch" so by the recent relaxation of the 
> rules  an OCA isn't needed.
> 
> -phil.
> 
> On 6/28/2011 5:02 AM, Anthony Petrov wrote:
>> Hi Julien,
>>
>> For your contribution to be acceptable, you have to sign an OCA. 
>> Please refer to this page for details on how to become an OpenJDK 
>> contributor:
>>
>> http://openjdk.java.net/contribute/
>>
>> -- 
>> best regards,
>> Anthony
>>
>> On 6/27/2011 4:03 PM, gouessej at orange.fr wrote:
>>> Hi!
>>>
>>> I think I have found a fix for this bug. On GNOME and on KDE the 
>>> atoms remain unchanged according to xprops but the X client message 
>>> is sent, that is why I call XChangeProperty. On the other hand, only 
>>> a window on top of the stack can become fullscreen, that is why I use 
>>> _NET_WM_STATE_ABOVE. I fear that building OpenJDK requires a lot of 
>>> time. Could someone with a ready environment make a build for me with 
>>> this fix? My "patch" is in the bug report here:
>>> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7057287
>>>
>>> Best regards
>>>
>>> Julien Gouesse
>>>
>>>> Message du 23/06/11 14:50
>>>> De : "Anthony Petrov" A : gouessej at orange.fr
>>>> Copie à : Objet : Re:  KDE Task bar is always on top of fullscreen 
>>>> Java applications
>>>>
>>>> Hi,
>>>>
>>>> On 06/22/2011 02:28 PM, gouessej at orange.fr wrote:
>>>>> Yes, that's it. I'm sad because I'm using JOGL AWT canvas called
>>>>> GLCanvas and this bug impacts my first person shooter. If I knew
>>>>> better the source code of AWT, I would try to write a patch. I assume
>>>>> there is a way of detecting the window manager to apply this fix only
>>>>> in this case, isn't it?
>>>> This window state is a part of EWMH specification, so there's no 
>>>> need to set it for specific WMs only.
>>>>
>>>>
>>>>> Does AWT currently rely on xrandr or VidMode on Linux? Best regards.
>>>> I think this question belongs to the 2d-dev at openjdk mailing list. 
>>>> I'm not a Java2D expert. Please ask 2D folks about that.
>>>>
>>>> PS. Please remember to use Reply All rather than just Reply so that 
>>>> your message hits the mailing list.
>>>>
>>>> -- 
>>>> best regards,
>>>> Anthony
>>>>
>>>>>
>>>>>> Message du 22/06/11 12:11
>>>>>> De : "Anthony Petrov" A : gouessej at orange.fr
>>>>>> Copie à : awt-dev at openjdk.java.net
>>>>>> Objet : Re: KDE Task bar is always on top of fullscreen Java 
>>>>>> applications
>>>>>>
>>>>>> Hello,
>>>>>>
>>>>>> On 6/22/2011 1:14 PM, gouessej at orange.fr wrote:
>>>>>>> The exclusive fullscreen mode is broken in KDE for Java 
>>>>>>> applications as I explained here:
>>>>>>> https://bugs.kde.org/show_bug.cgi?id=276159
>>>>>>>
>>>>>>> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7057287
>>>>>>> (not yet visible)
>>>>>>>
>>>>>>> After some investigations, the problem comes from Java which does 
>>>>>>> not
>>>>>>> tag the window as fullscreen. Do you know how to fix this bug?
>>>>>> To tag full screen windows with the _NET_WM_STATE_FULLSCREEN 
>>>>>> state? That's easy. :)
>>>>>>
>>>>>> Thanks for filing the bug report. AWT team will take care of this 
>>>>>> issue.
>>>>>>
>>>>>> -- 
>>>>>> best regards,
>>>>>> Anthony
>>>>>>
>